# Based on VSPER theory,the number of 90 degree F-Br F angles in $BrF_5$ is

$\begin{array}{1 1}(a)\;8&(b)\; 6\\(c)\;4&(d)\;7\end{array}$

According VSEPR theory $BrF_5$ stable geomentry is square pyramid $(AB_5E)$ type
Four $90^{\large\circ}$s(F-Br-F)
There are $4F-Br-F \;90^{\large\circ}$ angles
Hence (c) is the correct answer.